Liquid chromatographic system

ABSTRACT

A liquid chromatographic system comprising an eluent supplying device, a column packed with a filling substance, an eluent guide tube having one end communicated with the column and the other end communicated with the supplying device through a specimen injector having a specimen measuring tube to measure a predetermined quantity of specimen sent from a specimen supplying device and to hold the measured specimen therein, and a specimen guide tube having one end inserted directly into the filling substance and the other end connected with the specimen injector.

' United States Patent 1191 Takeuchi et al.

[4 1 Jan. 21, 1975 LIQUID CHROMATOGRAPIIIC SYSTEM Inventors: Seiji Takeuchi, Hitachi; Yoshinori Takata; Kazunori Fujita, both of Ibaraki-ken, all of Japan Assignee: Hitachi Ltd., Tokyo, Japan Filed: Apr. 16, 1973 Appl. No.2 351,501

Foreign Application Priority Data Apr. 17, 1972 Japan 47-377l5 u.s. c|....." 210/198 0 Int. Cl B0ld 15/08 Field of Search 210/31 C, 198 C References Cited UNITED STATES PATENTS 5/1969 Bakalyaa et al 210/31 C X 187 SWITCHING CIRCUIT SYNCHRONOUS CIRCUIT 3,5l0,27l 5/l970 Emncus et al. 2l0/l98 C X Primary Examiner-J0hn Adee Attorney, Agent, or FirmCraig & Antonelli 571 ABSTRACT A liquid chromatographic system comprising an eluent supplying device, a column packed with a filling substance, an eluent guide tube having one end communicated with the column and the other end communicated with the supplying device through a specimen injector having a specimen measuring tube to measure a predetermined quantity of specimen sent from a specimen supplying device and to hold the measured specimen therein, and a specimen guide tube having one end inserted directly into the filling substance and the other end connected with the specimen injector.

26 Claims, 10 Drawing Figures mamm l I915 I 3.862.038

SHEET 10F 6 F I G. 2

l7 3 SWITCHING 3 CIRCUIT I I8 SYNCHRONOUS CIRCUIT Pmm mm 197s SHEET 2 OF 6 F|G..I, PRIOR-ART To DETECTOR PATENTED JAN 2 1 I975 SHEET 5 OF 6 FIG. 5A

ELUTION TIME (minute) Fl G.5B

ELUT ION TIME (minuf) PATENTEB JAN 21 I975 SHEET 6 BF 6 F lG.6

N E M C E S TO COLUMN LIQUID CHROMATOGRAPHIC SYSTEM BACKGROUND OF THE INVENTION 1. FIELD OF THE INVENTION DESCRIPTION OF THE PREFERRED EMBODIMENTS Before explaining the present invention by way of The present invention relates to a liquid chromatoembodiments, the prior art will be mentioned with refgraphic system and more particularly to a liquidchromatographic system in which the specimen can be prevented from diffusing at the specimen introducing part of the column.

2. DESCRIPTION OF THE PRIOR ART In general, the sensitivity of the detector and the way of specimen introduction are the most important factors in achieving a high speed separation in chromatography. Especially in case of high pressure liquid chromatography in which the column contains such a filling substance or filler as ion exchange resin, the filler sometimes swells and sometimes contracts depending upon the kinds of separation developing substances or eluting developers (or eluents) introduced into the column through a high pressure duct. Consequently, the volume of the space defined between the top of the filler and the specimen introducing hole so that the result of the analysis is adversely affected. It is therefore very useful in high pressure liquid chromatography to improve the mechanism to introduce the specimen into the column.

SUMMARY OF THE INVENTION One object of the present invention is to provide a high liquid-chromatographic system in which the specimen can be prevented from diffusing at the specimen introducing part.

Another object of the present invention is to provide a liquid-chromatographic system capable of a rapid analysis with high accuracy.

According to one of the preferred embodiments of the present invention, there is provided a liquidchromatographic system comprising an eluent supplying device, a column packed with a filling substance, an eluent guide tube having one end communicated with the column and the other end connected with the eluent supplying device, and a specimen introducing tube having one end inserted directly into the filling substance packed in the column and the other end connected with a specimen supplying device.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 shows the schematic structure of a conventional apparatus for use in liquid chromatography.

FIG. 2 shows the schematic structure as a whole of an apparatus for use in a liquid-chromatographic systern embodying the present invention.

FIGS. 3A and 3B show the perspective and top views of a specimen injector used in the apparatus shown in FIG. 2.

FIG. 4 illustrates the condition of connecting the specimen injector shown in FIG. 3 with a column.

FIGS. 5A and 5B are respectively chromatograms obtained by the conventional chromatographic and the chromatographic system according to the present invention.

FIG. 6 shows the cross section of the principal part of another example of a column as used in the chromatographic system shown in FIG. 2.

FIGS. 7A and 7B show another example of a specimen injector as used in the chromatographic system shown in FIG. 2.

erence to FIG. 1.

In FIG. 1 which shows the structure of a conventional chromatographic system there are illustrated a tank 41 containing an eluting developer or eluent, a pump 42 to compress and feed the eluent into a pressure gauge 43 to measure the output pressure of the pump 42, a specimen injector 44 having a change-over valve such as a flow injector, a specimen introducing tube 45, a packing 46, a column filler 47, a stainless steel column 48, a filter 49, a packing 50, a space 51 between the specimen guide tube 45 and the column filler 47 and a guide tube shifter 52 to shift the specimen guide tube 45.

According to a conventional method of introducing a specimen into the column, using such a structure as described above, the specimen introducing device as indicated at A in FIG. 1 is used. First, a specimen is taken into the flow injector 44, then the specimen is introduced through the specimen introducing tube 45 into the column 48, and finally the specimen is therein eluted. According to this conventional method, however, the filler 47 packed in the column, e.g., organic polymeric adsorbent and ion exchange resin, will be compressed and shrink under the action of the high pressure of about kg/cm at which the specimen is transported through a high-pressure duct and the space 51 is created between the end of the specimen introducing tube 45 and the filler 47 so that the specimen introduced into the column 48 is diffused and diluted. Consequently, the width of each peak of the resultant chromatogram is broadened and therefore the separation of peaks is degraded. In order to avoid this drawback, an additional amount of the filler 47 must often be supplied into the column 48 so that the efficiency of analysis will necessarily be reduced.

Another conventional method of chromatography has employed a specimen introducing device as designated at B in FIG. 1. In this case, the specimen transported through a high pressure duct is introduced through the specimen introducing tube 45 fixed to the shifter 52 into the column 48 and expanded. In this method, the column 48 must be made of stainless steel to withstand the high pressure at which the specimen is maintained. Stainless steel is not transparent and it is impossible to externally observe the variation in the space. Therefore, it is necessary to manipulate the guide tube shifter 52 only through inexact finger touch and to bring the specimen introducing tube 45 in contact with the filler 47. It has, however, proved that such an operation can hardly be performed properly.

FIG. 2 is the general view of a liquidchromatographic system embodying the present invention. Each of tanks 1 and 2 contains an eluent. Pumps 3 and 4 serve to feed the eluent. The tanks 1 and 2 and the pumps 3 and 4 constitute an elute supplying device. A column 5 is packed with a filler 6. A specimen injector 7 is of loop valve type and has a specimen measuring and holding tube 8 to measure a predetermined quatity of specimen from a specimen supplying device (not shown) and to hold the measured specimen therein. Guide tubes 9, 9' and 9" are communicated at one-ends thereof with the column and at the other ends thereof with the eluent supplying device and serve to introduce the eluent from the device into the column through the specimen injector 7 and an electromagnetic valve 10. A specimen introducing tube 11 has its one end inserted into the filler 6 in the column through an electromagnetic valve 12 and the other end coupled through the specimen injector 7 to the specimen supplying device not shown in the figure. A detector 13' detects the specimen out of the column 5 and is coupled to a recorder 13. A motor 14 drives the loop valve type specimen injector 7 and motors l5 and 16 actuate the electromagnetic valves and 12. A switching circuit 17 controls the switching operation of the motors l4, l5 and 16. A synchronous circuit 18 serves to synchronously actuate these motors 14, and 16.

Under normal condition, the eluent is fed by means of the pump 3 into the guide tube 9 and further fed into the column 5 via the loop valve type specimen injector 7 and the electromagnetic valve 10. During the above operation, the pump 4 is kept stopped. In the process of specimen injection, a predetermined quantity of the specimen is held in the measuring and holding tube 8 during the normal condition and the specimen is directly injected out of the specimen introducing tube 11 into the column filler 6. The operation of the associated mechanisms is as follows. Namely, the switching circuit 17 is actuated to actuate the synchronous circuit 18, which then drives the motors 14, 15 and 16. Accordingly, the electromagnetic valve 10 is closed, to stop the pump and simultaneously the electromagnetic valve 12 is opened to start the pump 4. In this way, the specimen in the tube 8 is pushed by the eluent and introduced into the column through the electromagnetic valve 12 and the specimen introducing tube 11. Then, the specimen is eluted and developed in the column 5 and the thus processed specimen is poured out of the bottom of the column 5, detected by the detector 13' and recorded on the recorder 13.

The switching circuit 17, which performs such an operation as described above when operated along with the synchronous circuit 18, can actuate separately the specimen injector 7 and the electromagnetic valve 10 and 12 through appropriate selection of the switch so that it is also possible to introduce the specimen and/or the eluent into the column 5 at the top of and through the side wall of the column 5 and to simultaneously perform the introduction of the specimen and the eluent.

FIGS. 3A and 3B respectively represent the perspective and top views of such a specimen injector as indicated at numeral 7 in FIG. 2. In FIG. 3A, the loop valve 7 comprises upper and lower members 19 and 20 slidably connected with each other and the lower member 20 is rotated on the sliding surface 21 relative to the upper member 19. Two narrow, concentric circular grooves are cut in the sliding surface, the outer groove consisting of a groove 22 indicated by dotted line and a groove 23 indicated by solid line constructed independent of each other and each of the grooves 22 and 23 subtending an angle of 60 with respect to the center and the inner groove being continuously cut to always maintain the communicating condition, as seen in FIG. 3B. The upper member 19 of the loop valve 5 is maintained stationary and connected with a plurality of pipes coupled to distributing systems. The pipes 25 and 26 are respectively the entrance and the exit for the specimen. Under the normal condition, the upper and the lower members 19 and 20 of the loop valve 7 are communicated with each other through the groove 22 so that the eluent is fed by the pump 3 into the guide tube 9. The eluent is then sent into the column 5 through the inner groove 24 and the guide tube 9. When the switching circuit 17 is actuated, the loop valve 7 is rotated and the groove of the sliding surface 21 communicates with the groove 23. At this time, the pump 3 is stopped, the electromagnetic valve 10 is closed, the pump 4 is in turn started, and the eluent is introduced into the tube 9" to push out a predetermined quantity of specimen held in the measuring tube 8 so that the specimen may be introduced through the guide tube 11 into the column 5.

For the actual measurement, the chromatogram may be obtained with the chromatographic system being in the stage described above, but there is another way of obtaining the chromatogram, in which the switching circuit 17 is actuated again to restore the system in the normal condition so that the eluent is poured into the column at the top thereof after the specimen has been injected. It is also possible to simultaneously introduce the specimen and the eluent into the column 5 respectively through the tube 11 and the tube 9 by separately actuating the electromagnetic valve 10 and the pump 3.

FIG. 3B is the top view of the loop valve 7 described above, especially of the connecting part thereof. From the figure, it will be seen that the inner groove 24 is always maintained in a communicating condition and the other groove communicates with the groove 22 and the groove 23 by the rotation of the lower member 20 of the loop valve by towards right and left.

FIG. 4 illustrates a concrete way of connecting the column 5 and the loop valve 7 shown in FIG. 3. In this figure and all through the attached drawings except FIG. 1, the same reference numerals and characters are applied to equivalent parts or elements. Between the top of the column 5 and the filler 6 is a space 27 and the column is tipped with column caps 28 to obtain hermetical sealing. A column envelope 29 has an inlet and outlet ports 30 and 31 through which water having a constant temperature is taken in and out to circulate around the column 5. Packings 32 are used with the column caps 28 to facilitate the hermetical sealing. Filters 33 serve to prevent the filler from flowing out of the column. In this case, the specimen introducing tube 11 penetrates the side wall of the column 5 and is inserted into the column filler 6. The position of the penetration of the tube 11 through the wall is located below that level of the top of the filler which is assumed when the filler 6 contracts due to the high pressure liquid flowing into the column 5.

In the normal state, the pump 3 is operated and the eluent is passed through the inner grove 24 of the loop valve 7. The eluent is then fed into the column 5 through the guide tube 9 and the valve 10 and after reaching the state in equilibrium with the filler 6 finally fed to the detector 13' to be recorded. This recorded data becomes the base line of the chromatogram obtained thereafter. At this time, the specimen measuring tube 8 measures a constant quantity of specimen by the suction through the specimen outlet port 26 since the specimen inlet port 25 is connected with the specimen supplying device not shown in the figure. When the loop valve 7 is rotated through an angel of 60, the pump 3 is stopped. Then, the valve 10 is opened and simultaneously the pump 2 is operated and the valve 12 is opened. The eluent fed from the tank 2 to the pump 4 is caused to flow through the tube 9" and the groove 23 in the sliding surface 21 so as to push out the measured specimen in the tube 8. The specimen pushed out by the eluent is fed into the column 5 through the specimen introducing tube 11 and the valve 12. The specimen in the column 5 is eluted and developed, decomposed into individual constituents and the separated components are detected by the detector 13 to be converted into the corresponding electrical signals which is recorded on the recorder 13.

FIGS. 5A and 5B show the examples of the chromatograms obtained by the chromatographic-system according to the conventional method and the method of the present invention, respectively. In order to obtain the chromatograms for comparison, the same chemicals are commonly used in the conventional chromatographic system and the chromatographic system of the present invention. Namely, Aminex A-4 positive ion exchange resin is used for filler; Alkaline earth metals such as Mg, Ca, Sr and Ba for the specimen; and a buffer solution of ammonium acetate for the eluent. In FIGS. 5A and 5B, the peaks b, c and d correspond to Mg, Ca, Sr and Ba, respectively. As seen from the figures, the peaks (FIG. 5A) according to the convenctional chromatographic system are broader than those (FIG. 53) according to the chromatographic system of the present invention. Namely, the separations between the peaks, especially that between the peaks a and b in FIG. 5A, is poor while the separations in FIG. 5B is better. Therefore, a chromatogram having a much better separation can be obtained according to the present invention.

In the embodiment described above, it is also possible to use a single pump and a single tank instead of the pumps 3 and 4 and the tanks 1 and 2 or to use a plurality of eluents so as to perform a similar analysis. And it is further possible to introduce the eluent through the tube 9 into the column 5 by changing over the switch after the introduction of the specimen due to the selecting operation of the switch.

As has hitherto been described in detail, according to one embodiment of the present invention, the specimen introducing tube penetrates the side wall of the column and inserted directly into the tiller, the specimen is pushed into the column by the eluent, and another guide tube to introduce the eluent is provided at the top of the column. With this structure, the dilution and the diffusion of the specimen to be analyzed, due to the contraction of the filler by the high pressure solution flowing into the column and the resulting spaced formed in the column, can be prevented, that is, the broadening of the peak widths in the chromatogram and the degradation of the peak separation can be prevented.

In the embodiment, the specimen introducing tube is so provided as to penetrate the side wall of the column while the eluent guide tube is communicated with the column through the top of the column. It is also possible to send both the tubes through the top of the column into the column and especially to construct the tubes in coaxial structure at the top of the column, in which the inner tube and the outer tube serve respectively at the specimen introducing tube and the eluent guide tube. FIG. 6 shows such an example of a coaxial double tube. The explanation of the respective parts in FIG. 6 is not given here since they are similar to those cap 28 with the column 5 and the specimen introducing tube 11 is passed through the guide tube 9 and inserted directly into the filler 6. With this structure, the specimen and the eluent are both introduced into the column through the column cap 28 provided at the top of the column and the rapid analyis of the specimen can be carried out through an operation similar to that described above. Further, It is also possible to send both the tubes separately or in double structure into the column through the side wall, the bottom column cap or the side wall near the bottom of the column. The length Ls between the end of the specimen introducing tube 11 and the end of the column should be chosen to be 10% of the total length of the column. This length is slightly larger than that of the space defined between the end of the column and the top level of the contracted filler which, of all the usable fillers selected, has the largest contraction coefficient.

In case where the specimen introducing tube and the eluent guide tube are separately provided in the side wall of the column, the position of the former should be chosen to be slightly lower than that of the latter. FIGS. 7A and 7B show two alternative change-over states of the valve of a specimen injector as another embodiment of the present invention. In FIG. 7A which shows the normal state, the eluent is directly introduced into the column 5 and in the meanwhile a predetermined quantity of specimen is measured by and held in the measuring tube 8. When the state shown in FIG. 5A is changed over th the other one shown in FIG. 58 by rotating the valve through an angle of 60, the specimen held in the measuring tube 8 is pushed out by the eluent and introduced directly into the column 5. Therefore, if the specimen injector of this type is employed, one of the tubes 9 and 11 can be eliminated. Namely, a single tube, which is directly inserted into the filler 6 of the column 5 through the top, the side wall or the bottom of the column 5, can serve as both the specimen introducing tube 11 and the eluent guide tube 9.

As described often in the foregoing lines of this speci fication, according to the present invention, the specimen introducing tube is inserted directly into the tiller contained in the column so that the dilution and diffusion of the specimen introduced into the column due to the contraction of the filler owing to the high pressure liquid flowing into the column can be prevented. Therefore, a better chromatogram can be obtained from the specimen and the rapid analysis becomes possible.

We claim:

1. A liquid-chromatographic system comprising a column packed with a filler, a specimen supplying means for supplying a specimen to be separated, an eluent supplying means for supplying an eluent, said cluent eluting and developing said specimen within said column, a flow path change-over means connected with said specimen supplying device and said eluent supplying device for selectively supplying said speeimen and said eluent to said column, an eluent guide tube having a first end communicated with said column and a second end connected with said flow path change-over means, a specimen introducing tube having a first open end penetrating into said filler in said column and a second end connected with said flow path change-over means, and a detecting means for detecting the eluted and developed specimen from said column.

2. A liquid-chromatographic system as claimed in claim 1, wherein said first open end of said specimen introducing tube penetrates into said filler in said column through a side wall of said column.

3. A liquid-chromatographic system as claimed in claim 1, wherein said first open end of said specimen introducing tube penetrates into said filler of said column through the ceiling of said column.

4. A liquid-chromatographic system as claimed in claim 1, wherein said first open end of said specimen introducing tube penetrates into said filler in said column through the bottom of said column.

5. A liquid-chromatographic system as claimed in claim 1, wherein said first end of said eluent, guide tube is communicated with said column at the top of said column.

6. A liquid-chromatographic system as claimed in claim 2, wherein said first end of said eluent guide tube is communicated with said column at the top of said column.

7. A liquid-chromatographic system as claimed in claim 3, wherein said first end of said eluent guide tube is connected into said column through the top ceiling of said column, said specimen introducing tube being contained within said eluent guide tube at a portion of said eluent guide tube connected into said column such that a flow path of said eluent is formed between the outer wall of said specimen introducing tube and the inner wall of said eluent guide tube.

8. A liquid-chromatographic system as claimed in claim 7, wherein said specimen introducing tube and said eluent guide tube form a coaxial double tube structure at the top of said column.

9. A liquid-chromatographic system as claimed in claim 2, wherein said first end of said eluent guide tube is connected into said column through the side wall of said column, said specimen introducing tube being contained within said eluent guide tube at a portion of said eluent guide tube connected into said column such that a flow path of said eluent is formed between the outer wall of said specimen introducing tube and the inner wall of said eluent guide tube.

10. A liquid-chromatographic system as claimed in claim 1, wherein said flow path change-over means includes a specimen measuring tube for measuring a predetermined quantity of specimen, and said flow path change-over means includes means for holding specimen supplied form said specimen supplying device in said specimen measuring tube and means for introducing said specimen held in said specimen measuring tube into said column through said specimen introducing tube by action of the eluent supplied from said eluent supplying device.

11. A liquid-chromatographic system as claimed in claim 10, wherein said first open end of said specimen introducing tube penetrates into said filler in said column through the side wall of said column, the position of said first open end of said specimen introducing tube being lower than that of said first end of said eluent guide tube.

12. A liquid-chromatographic system as claimed in claim 10, wherein said first open end of said specimen introducing tube penetrates into said filler in said column through the ceiling of said column, the position of said first open end of said specimen introducing tube being lower than that of said first end of said eluent guide tube.

13. A liquid-chromatographic system as claimed in claim 10, wherein said first open end of said specimen introducing tube penetrates into said filler in said column through the bottom of said column, the position of said first open end of said specimen introducing tube being lower than that of said first end of said eluent guide tube.

14. A liquid-chromatographic system as claimed in claim 1, wherein said filler is an ion exchange resin.

15. A liquid-chromatographic system as claimed in claim 1, wherein said first open end of said specimen introducing tube penetrates into said filler in said column at a position lower than the position at which said first end of said eluent guide tube communicates with said column.

16. A liquid-chromatographic system as claimed in claim 15, wherein both said specimen introducing tube and said eluent guide tube are connected into the top of said column, and said first open end of said specimen introducing tube penetrates through the top level of said filler in said column. 7

17. A liquid-chromatographic system as claimed in claim 16, wherein said first open end of said specimen introducing tube isat a distance below said top of said column at least 10% of the total length of said column.

18. A liquid-chromatographic system as claimed in claim 1, wherein said flow path change-over means includes an upper and lower member in slidable contact, said lower member being rotatable with respect to said upper member at a surface of slidable contact.

19. A liquid-chromatographic system as claimed in claim 18, wherein two concentric circular grooves are provided in said surface of slidable contact, a first of said two circular grooves formed of groove segments with alternate groove segments being independent of one another, said alternate groove segments coming into communication with one another by rotation of said lower member.

20. A liquid-chromatographic system as claimed in claim 19, wherein said eluent supplying means includes two reservoirs of eluent, a first of said two reservoirs being connected to said first of said two circular grooves, and a second of said two reservoirs being connected to a second of said two circular grooves, said second circular groove being connected to said eluent guide tube.

21. A liquid-chromatographic system as claimed in claim 20, wherein said specimen supplying means is connected to said first of said two circular grooves and said specimen introducing tube is connected to said first circular groove, each of said specimen supplying means, said specimen introducing tube and said first of said two reservoirs being connected to different ones of said alternate groove segments.

22. A liquid-chromatographic system as claimed in claim 21, wherein said flow path change-over means further includes specimen measuring means, said specimen measuring means having first and second ends connecting different ones of said alternate groove segments of said first circular groove to be in selective communication with said first reservoir and said specimen introducing tube or said specimen supplying means upon rotation of said lower member.

23. A liquid-chromatographic system comprising a column packed with a filler, a specimen supplying device for supplying a specimen, and eluent supplying device for compressing and supplying an eluent, a flow path change-over means connected with said specimen supplying device and said eluent supplying device, said flow path change-over means including a specimen measuring tube for measuring a predetermined quantity of specimen, a conduit having a first open end penetrating into said filler in said column and a second end connected with said flow path change-over means, a means for holding said specimen supplied from said specimen supplying device in said specimen measuring tube and for introducing said specimen held in said specimen measuring tube into said column through said conduit by action of eluent supplied from said eluent supplying device, and a detector for detecting the spec imen from said column, whereby, by a selective change-over operation of said flow path change-over means and through said specimen measuring tube, said specimen supplying device and said conduit are selectively communicated with and disconnected from each other, and said eluent supplying device and said conduit are selectively communicated with and disconnected from each other, so that only eluent or both of eluent and specimen pushed by said eluent is intro duced into said filler in said column.

24. A liquid-chromatographic system as claimed in claim 23, wherein said first open end of said conduit penetrates into said filler in said column through the side wall of said column.

25. A liquid-chromatographic system as claimed in claim 23, wherein said first open end of said conduit penetrates into said filler in said column through the bottom of said column.

26. A liquid-chromatographic system as claimed in claim 23, wherein said first open end of said conduit penetrates into said filler in said column through the 

1. A liquid-chromatographic system comprising a column packed with a filler, a specimen supplying means for supplying a specimen to be separated, an eluent supplying means for supplying an eluent, said eluent eluting and developing said specimen within said column, a flow path change-over means connected with said specimen supplying device and said eluent supplying device for selectively supplying said specimen and said eluent to said column, an eluent guide tube having a first end communicated with said column and a second end connected with said flow path change-over means, a specimen introducing tube having a first open end penetrating into said filler in said column and a second end connected with said flow path change-over means, and a detecting means for detecting the eluted and developed specimen from said column.
 2. A liquid-chromatographic system as claimed in claim 1, wherein said first open end of said specimen introducing tube penetrates into said filler in said column through a side wall of said column.
 3. A liquid-chromatographic system as claimed in claim 1, wherein said first open end of said specimen introducing tube penetrates into said filler of said column through the ceiling of said column.
 4. A liquid-chromatographic system as claimed in claim 1, wherein said first open end of said specimen introducing tube penetrates into said filler in said column through the bottom of said column.
 5. A liquid-chromatographic system as claimed in claim 1, wherein said first end of said eluent, guide tube is communicated with said column at the top of said column.
 6. A liquid-chromatographic system as claimed in claim 2, wherein said first end of said eluent guide tube is communicated with said column at the top of said column.
 7. A liquid-chromatographic system as claimed in claim 3, wherein said first end of said eluent guide tube is connected into said column through the top ceiling of said column, said specimen introducing tube being contained within said eluent guide tube at a portion of said eluent guide tube connected into said column such that a flow path of said eluent is formed between the outer wall of said specimen introducing tube and the inner wall of said eluent guide tube.
 8. A liquid-chromatographic system as claimed in claim 7, wherein said specimen introducing tube and said eluent guide tube form a coaxial double tube structure at the top of said column.
 9. A liquid-chromatographic system as claimed in claim 2, wherein said first end of said eluent guide tube is connected into said column through the side wall of said column, said specimen introducing tube being contained within said eluent guide tube at a portion of said eluent guide tube connected into said column such that a flow path of said eluent is formed between the outer wall of said specimen introducing tube and the inner wall of said eluent guide tube.
 10. A liquid-chromatographic system as claimed in claim 1, wherein said flow path change-over means includes a specimen measuring tube for mEasuring a predetermined quantity of specimen, and said flow path change-over means includes means for holding specimen supplied form said specimen supplying device in said specimen measuring tube and means for introducing said specimen held in said specimen measuring tube into said column through said specimen introducing tube by action of the eluent supplied from said eluent supplying device.
 11. A liquid-chromatographic system as claimed in claim 10, wherein said first open end of said specimen introducing tube penetrates into said filler in said column through the side wall of said column, the position of said first open end of said specimen introducing tube being lower than that of said first end of said eluent guide tube.
 12. A liquid-chromatographic system as claimed in claim 10, wherein said first open end of said specimen introducing tube penetrates into said filler in said column through the ceiling of said column, the position of said first open end of said specimen introducing tube being lower than that of said first end of said eluent guide tube.
 13. A liquid-chromatographic system as claimed in claim 10, wherein said first open end of said specimen introducing tube penetrates into said filler in said column through the bottom of said column, the position of said first open end of said specimen introducing tube being lower than that of said first end of said eluent guide tube.
 14. A liquid-chromatographic system as claimed in claim 1, wherein said filler is an ion exchange resin.
 15. A liquid-chromatographic system as claimed in claim 1, wherein said first open end of said specimen introducing tube penetrates into said filler in said column at a position lower than the position at which said first end of said eluent guide tube communicates with said column.
 16. A liquid-chromatographic system as claimed in claim 15, wherein both said specimen introducing tube and said eluent guide tube are connected into the top of said column, and said first open end of said specimen introducing tube penetrates through the top level of said filler in said column.
 17. A liquid-chromatographic system as claimed in claim 16, wherein said first open end of said specimen introducing tube is at a distance below said top of said column at least 10% of the total length of said column.
 18. A liquid-chromatographic system as claimed in claim 1, wherein said flow path change-over means includes an upper and lower member in slidable contact, said lower member being rotatable with respect to said upper member at a surface of slidable contact.
 19. A liquid-chromatographic system as claimed in claim 18, wherein two concentric circular grooves are provided in said surface of slidable contact, a first of said two circular grooves formed of groove segments with alternate groove segments being independent of one another, said alternate groove segments coming into communication with one another by rotation of said lower member.
 20. A liquid-chromatographic system as claimed in claim 19, wherein said eluent supplying means includes two reservoirs of eluent, a first of said two reservoirs being connected to said first of said two circular grooves, and a second of said two reservoirs being connected to a second of said two circular grooves, said second circular groove being connected to said eluent guide tube.
 21. A liquid-chromatographic system as claimed in claim 20, wherein said specimen supplying means is connected to said first of said two circular grooves and said specimen introducing tube is connected to said first circular groove, each of said specimen supplying means, said specimen introducing tube and said first of said two reservoirs being connected to different ones of said alternate groove segments.
 22. A liquid-chromatographic system as claimed in claim 21, wherein said flow path change-over means further includes specimen measuring means, said specimen measuring means having first and second ends connecting different ones of said alternate grooVe segments of said first circular groove to be in selective communication with said first reservoir and said specimen introducing tube or said specimen supplying means upon rotation of said lower member.
 23. A liquid-chromatographic system comprising a column packed with a filler, a specimen supplying device for supplying a specimen, and eluent supplying device for compressing and supplying an eluent, a flow path change-over means connected with said specimen supplying device and said eluent supplying device, said flow path change-over means including a specimen measuring tube for measuring a predetermined quantity of specimen, a conduit having a first open end penetrating into said filler in said column and a second end connected with said flow path change-over means, a means for holding said specimen supplied from said specimen supplying device in said specimen measuring tube and for introducing said specimen held in said specimen measuring tube into said column through said conduit by action of eluent supplied from said eluent supplying device, and a detector for detecting the specimen from said column, whereby, by a selective change-over operation of said flow path change-over means and through said specimen measuring tube, said specimen supplying device and said conduit are selectively communicated with and disconnected from each other, and said eluent supplying device and said conduit are selectively communicated with and disconnected from each other, so that only eluent or both of eluent and specimen pushed by said eluent is introduced into said filler in said column.
 24. A liquid-chromatographic system as claimed in claim 23, wherein said first open end of said conduit penetrates into said filler in said column through the side wall of said column.
 25. A liquid-chromatographic system as claimed in claim 23, wherein said first open end of said conduit penetrates into said filler in said column through the bottom of said column.
 26. A liquid-chromatographic system as claimed in claim 23, wherein said first open end of said conduit penetrates into said filler in said column through the bottom of said column. 